Blank page when FB login

First off, very sorry for the delay! There's a few possible causes for that problem, but looking at your site, the most likely culprit is an issue with a profile plugin. Please try the following and see if anything helps narrow down the problem:
* First, disable *all* JFBCProfile plugins you might have enabled. Then try to login again. If it works, re-enable any profile plugins you have enabled one-by-one and see when the site crashes again. You really should only have the JomSocial profile plugin enabled and maybe one or two others *if* you have other extensions. Do not enable all the plugins though unless you're sure you need them.
* If that doesn't help, re-enable Error Reporting and then turn off GZip compression. If you have any other 'optimization' extensions enabled, disable those as well. That will hopefully show a prettier PHP error on that page and help us narrow things down.

If that doesn't help, just let us know and we'll do what we can to help narrow things further.

Thanks,
Alex

The profile plugins let you import a user's profile into the specified extension, like K2 or JomSocial. We don't have a configuration guide on each individual plugin because they all behave pretty much the same. The only difference is the extension they are meant to import the user's profile into.

If you don't use K2's profile system (mainly used if you let your users create K2 items and somewhat for commenting), you really don't need the K2 Profile Plugin.

If you think you need it, let us know, and we can investigate the redirection issues. That's not something we've heard of before though.

Thanks,
Alex